Process for making gas



J. U. MCDONALD.

PROCESS FOR MAKING GAS.

APPLICATION FILED MAR. 2, 1921.

' Reissued Mar. 28, 1922.

INVENTOR.

' WbR/VEY.

umii'ao STATES JOHN URBAN MCDONALD, or nncarua, limiters.

raocnss Ion mmo GAB.-

reillue filed March 2, 1921. Serial No. 449,224.

My invention'relates to the manufacture of gas for heating, illuminatingand power purposes by the destructive distillation of carbonaceousmatter, especially coal, peat, saw-mill refuse, wood, garbage and otheror anic material in general. 0

he object of this invention is the production of permanent; gases fromwet carbonaceous material at. mmimum'cost without the use of theexpensive mineral oils now usually em loyed.

further object of this invention is the.

conversion of all of the gas producing constituents of the carbonaceousmaterial including the tar, and the-moisture content, into gas, so as tothereby obtain a maximum revenue from the material acted upon.

This invention consists in heating the wet gas producing material in aretort which is so cohstructed that thesteam and gases produced by suchheating cannot escape from above the heated zone but are forced down bytheir own pressure through the heated zone where chemical action causesthe gas producing material to become intensely hot and thereby alsocauses an increased production of gases which are carried away frombelow the incandescent material.

The invention further consists in conveying the gas from -below thehighly heated gas-forming material through fresh amounts of suchmaterial so that the heat of the gas will be conserved by communicatingit to the fresh gas-forming material.

The accompanying drawing represents a. diagrammatic section of a devicewhich may be employed to carry this process into effect.

The retort .1 ma be of any desired cross section but is pre erablycylindrical and is mounted in a heating chamber 2 so that it may behighly heated, particularly intermediate its ends. The heating chamberconnects to a furnace 3 and may be provided with a flue 4 and anauxiliary air passage 5. Any other desired type of heating device ma beem loyed.

bove t e retort is mounted a feeding 56 chamber 6 provided with spiders.7 to support the helical conveyer 8 by means of which the wet gasproducing material 9 is fed down into the retort, should such materialfail to be moved by gravity, the rate of such feeding depending upon thecharacter of the material, the heat that is maintained in the retort,and the rate of reduction of the material to gas. The conveyer isshownmount ed on a shaft 11 having a. bevel gear 12 near one end, which earmeshes with the bevel gear 13 on the s aft 14 that is driven by a .motor15 by means of a belt 16.

vAbove the feeding chamber is a charge chamber 17 and between the twochambers is a valve 18. Above the'charge chamber is shown a hopper 19oflany desired construction, while a valve 20 is placed between it andthe charge chamber; The carbonaceous material is permit-ted to fall intothe charge chamber 17 in batches, after which the valve 20 is closed andthe valve 18 opened to permit the batch to fill the feeding chamber fromwhich the material passes to the retort at a constant rate. After thedesired amount has fallen into the feeding chamber the valve 18 isclosed to prevent the escape'of gases from the feeding chamber.

The retort is heated to such a temperature that a portion of thecarbonaceous material becomes incandescent and the volatile portionsthereof are driven off. At the same time, the moisture in thismaterialbecomes superheated steam, a pressure of mixed gas and steamaccumulating in the upper part of the retort and resulting in gas andsteam being forced down through the hot carbonaceous material.

Tliesteam in passing through the bed of incandescent carbon becomesdissociated, the oxygen combines with the carbon to produce carbonmonoxide and dioxide, the hydrogen upon being liberated mixes with themass of combined gases, a fractional portion unitin with carbon to formmarsh gas (CH A l of the gas producing material is therefore changed togas. The gases thus produced collect below the incandescent zone andpass out through the pipe 22. If the amount of moisture in thecarbonaceous matter is below the maximum that can be properly split upin the retort, a proper amount of superheated steam may be added throughthe pi 24 which connects to any proper source 0 sup- P Specification ofReissued Letters latent. Beissued Elam, 28, 1922,

Original No. 1,367,321, dated February 1, 1921, Serial No. 364,651,filed. March 10, 1920. Application for y. The waste passes to the bottomof the retort into trough 26, from which it is removed in. any desiredmanner. In the drawing, ascrew conveyer 27 is shown which carries thewaste to a passage 28 controlled by a valve 29. Thispasa-ge opens into achamber 30 containing a screw conveyor 31 which discharges; the wasteinto a receptacle 32. The two conveye'rs may be driven by a a motor 33.

The gas from the pipe 22 may be passed through the charge in the chamber17 where it gives .ofi' its heat to the fresh material therein, and thenpasses to the pipe 34 through the pipe'37. The three-way valve 36connects into the pipe 22 and to the pipe 35 so that the gas may passdirectly to the pipe 34 without passing through the cham- The principaldeparture of this process from the prior art lie in the production ofgases and very hot steam above a zone or bed of incandescent carbon in achamber of such construction that thergases and steam are forced.bytheir own pressure. through this intensely hot zone, resultingin theproduc--- tion of a maximum amount of heating and power gases.

1. The process of making gas consisting in introducing wet garbage intothe top of a vertical retort, heating an intermediate zone of the retortsufficiently to render the fixed carbon of the garbageincandescent atthat point, therebyheating the garbage above the incandescent zonesufficiently to vaporize the moisture and gasify' the. volatile matterof the garbage, the resultant: v

interruptlng the operation of the retort,

gases, tar vapor and steam being forced down bytheir own pressurethroughthe incandescent layercausing all the incandescent carbon tooxidize to form fixed gases which pass down with the gases of thevolatile matter through the: ashes in the bottom of the retort, therebycausing the total gasifica tion of the combustible constituents of thegarbage. g i D '2. he process of maklng gas COIISIStIIIg' in introducingcarbonaceous gasmaking material into a: retortrheating an mtermediate"zone of the, retort sufficiently to render the fixed carbon of thecarbonaceous material incandescent atthat point, thereby heating thecarbonaceous material at one side ofthe incandescent zone sufficientlyto vaporize the moisture and gasify the volatile matter of thecarbonaceous material, the resultant gases, tar vapor and steam beingforced. by their own pressure through the incandescent layer causingallthe incandescent carbon to oxidize to formfixed gases which pass withthe gases of the volatile matterthrough the ashes in. the retort,thereby causing the total gasification of the combustible constituentsof the carbonaceous material, I superheated steam being admitted tosupply oxygen and hydrogen to cause this complete gasification of theincandescent carbon.

3. The process of making gas consisting in introducing carbonaceous gas-making I material at a substantially constant rate into the top of aclosed vertical retort with out interrupting the operation of said retort, heating an intermediate zone of the retort sufficiently to renderthe fixed carbon of the carbonaceous material incandescent at thatpoint, thereby heating the carbonaceous material above the incandescentzone sufliciently to vaporize the moisture and gasify the volatilematter of the carbonaceous'material, the resultant gases, tar vapor andsteam being'forced down by their own pressure through theincandescentlayer causing all the incandescent carbon to combine withhydrogen and oxygen to form fixed. gases which pass down with the gasesof the volatile'matter through the ashes in. the bottom of the retort,thereby causing the total gasification of the combustible constituentsof the carbonaceous material, superheated steam being admit ted tosupply oxygen to cause this complete gasification of the incandescentcarbon.

4. The process of making gas consisting in introducing carbonaceous gasmaking material at a substantially constantrate into the top of a closedvertical retort without heating an intermediate zone of the retortsufiiciently to render the fixed carbon of the causing the incandescentcarbonto oxidize ases which passdown with.

to form fixed the gases of t e volatile matter, and permittmg the escapeof the gas from the retort below said zone.

JOHN URBAN McDONALD.

